Determination of heavy metal uptake in transgenic plants harbouring the rabbit CYP450 2E1 using X-ray fluorescence analysis

Transgenic Sesbania grandiflora (L.) pers (Fabaceae) and Arabidopsis thaliana (L.) (Brassicaceae) plants harbouring the rabbit cytochrome p450 2E1 enzyme were evaluated for their ability to accumulate heavy metals, potassium (K), calcium (Ca), manganese (Mn), zinc (Zn), copper (Cu), iron (Fe), lead (Pb) and bromine (Br), using X-ray Fluorescence analysis. When grown for 15?days on heavy metal-contaminated soils, transgenic cuttings of S. grandiflora and T3 A. thaliana plants recorded higher dry and fresh weight compared with their respective controls (A. thaliana and S. grandiflora plants transformed with an empty vector). Dry weight of transgenic S. grandiflora plants (0.321?g) was seven times higher than that of the wildtype (0.049?g), and the fresh weight (4.421?g) was about 4.6 times higher. Likewise, the dry weight of CYP450 2E1 A. thaliana (0.198?g) was more than eight times higher than that seen in the control (0.024?g). Moreover, Fe, Mn, K, and Ca concentrations in transgenic plants were significantly higher than those in their corresponding controls. For instance, concentrations of accumulated K (~3000 and 2000?mg/kg dry weight in S. grandiflora and A. thaliana, respectively) were significantly higher than those recorded in their corresponding controls (2500 and 1500?mg/kg, respectively). In the same vein, translocation of all studied metals from soils cultured with transgenic plants was higher than in those cultured with the control plants. In conclusion, the obtained results show the potential in using transgenic Sesbania and Arabidopsis plants harbouring the rabbit CYP450 2E1 for phytoremediation of mixed environmental contaminants.     

Oxidative stress responses of Daphnia magna exposed to TiO2 nanoparticles according to size fraction

Size is one of important factors determining titanium dioxide nanoparticle (TiO₂ NP) toxicity since penetration is eased with decreasing particle size and bioavailability is increased. The effect of particle size on oxidative stress against titanium dioxide nanoparticle (TiO₂ NP) exposure to Daphnia magna was investigated with both acute and chronic toxicity tests. Experiments on biochemical responses, repeatedly performed after size fractionation of the NPs using filtration, focused on the activities of four antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione-S-transferase (GST). In the chronic bioassay, the mortality was significantly increased at TiO₂ NP concentrations of 5 and 10 mg/L; however, no reduction of the reproduction ability was observed. Biochemical measurements showed that TiO₂ NP exposure significantly increased the antioxidant enzyme activities in D. magna. CAT, GPX and GST, but not SOD, showed a concentration-dependent increase. In terms of size fraction, particles ranging from 400 to 800 nm exhibited an increase of antioxidant enzyme activities in GST and GPX. These biochemical level observations suggested that TiO₂ NP toxicity was mediated by reactive oxygen species (ROS) generation via oxidative stress in D. magna. The increased mortality at the concentration of 5 mg/L in the chronic bioassay was attributed to accumulated TiO₂ NPs in the intestine of D. magna, which might induce effects such as oxidative stress relating to the induction of antioxidant enzymes.     

Health risk assessment for traffic policemen exposed to polycyclic aromatic hydrocarbons (PAHs) in Tianjin, China

In China, traffic policemen have to stand for several hours a day at the road intersections with high vehicle flows. To assess their exposure to airborne carcinogenic polycyclic aromatic hydrocarbons (PAHs) during their working time, a preliminary study was conducted to measure the personal exposure level to PAHs. And a probabilistic incremental lifetime cancer risk (ILCR) model together with the benzo[a]pyrene (BaP) toxic equivalents (BaP(eq)) method was used to conduct health risk assessment. Personal exposure monitors (PEM) were carried by traffic policemen to collect PM10 samples during their daily work in Tianjin, China. Meanwhile, PM100 samples were collected at the roadsides and on campus of Nankai University as comparison. PAHs species were quantitatively analyzed by GC/MS. Experimental results showed that the concentrations of total PAHs, BaP and BaP(eq) were much higher at the road intersections (867.5, 26.2, 82.4 ng m(-3)), where the traffic policemen stand during their work time, than those at the roadsides (46.6, 1.5, 5.7 ng m(-3)), and on campus (19.5, 0.7, 2.4 ng m(-3)). According to the risk assessment results, the occupational risk falls within the range from 10(-6) to 10(-3). On the basis of sensitivity analysis results, further research should be directed to give better characterization of the yearly concentration distribution of PAHs and the cancer slope factor (CSF) of BaP in order to improve the accuracy of the health risk assessment.     

Endocrine alteration and other biochemical responses in juvenile turbot exposed to the Prestige fuel oil

Juvenile turbot (Scophthalmus maximus) were exposed to different concentrations of the Prestige fuel oil through the diet. The effects on hepatic biotransformation enzymes, namely, 7-ethoxyresorufin O-deethylase (EROD), catalase, and phase II activities - UDP-glucuronosyltransferases (UGT) and cytosolic sulfotransferases (SULT) -, were monitored after 42-day exposure. Additionally, potential alterations on the endocrine system of juvenile turbot were assessed by measuring circulating levels of testosterone and 17beta-estradiol in plasma, together with gonadal P450 aromatase activity and the glucuronidation of testosterone by liver microsomal fractions. Fluorescent aromatic compounds (FACs) in bile were determined as an indicator of exposure to polycyclic aromatic hydrocarbons (PAHs). EROD activity increased in a dose dependent manner, and a positive correlation between levels of FACs in bile and EROD activity was observed. A significant increase in UGT activity was observed in fish exposed to medium and high fuel doses, whereas SULT cytosolic activity was not responsive to exposure. Exposure to the Prestige fuel oil sharply reduced circulating levels of testosterone in plasma. The obtained results suggest the ability of the Prestige fuel oil to alter hepatic biotransformation enzymes and to disrupt endogenous hormone levels in juvenile turbot, with unknown consequences in terms of sexual differentiation and reproduction.     

Health-risk assessment for workers exposed to polycyclic aromatic hydrocarbons (PAHs) in a carbon black manufacturing industry.

This study was established to assess workers' health-risks posed by PAHs exposures via both routes of inhalation and dermal contact. Personal inhalation exposure sampling was conducted on eight wet pelletizing workers and 22 packaging workers, by using a sampling train comprising an IOM personal inhalable aerosol sampler followed by an XAD-2 sorbent tube. Two workers were randomly selected from both exposure groups, and dermal exposures assessed by using soft polypropylene pads attached to the skin for nine different body surface areas for each selected worker. All personal inhalation and dermal samples were analyzed for 21 polycyclic aromatic hydrocarbon (PAH) species, and then converted to benzo[a]pyrene equivalent (BaPeq) concentrations by using the list of toxic equivalent factors (TEFs) suggested by Nisbet and LaGoy [Regul Toxicol Pharmocol 16 (1992) 290]. The resultant inhalation and dermal BaPeq exposure levels were used to estimate lifetime risks for lung cancer and skin cancer by using the BaP unit risks of 7.0 x 10(-2) (microg/m3)(-1) and 37.47(mg/kg bodyweight/day)(-1), respectively. Results show the personal inhalation BaPeq exposure levels for pelletizing and packaging workers were 622 and 774 ng/m3, respectively. The corresponding lifetime lung cancer risks estimated for both exposure groups were 4.35 x 10(-2) and 5.42 x 10(-2) respectively. For dermal exposures, results show personal dermal BaPeq exposure levels for both exposure groups were 0.664 and 0.847 microg/kg per day, respectively. The corresponding estimated lifetime skin cancer risks were 1.13 x 10(-3) and 1.56 x 10(-3), respectively. Although the estimated skin cancer risks were lower than the corresponding lung cancer risks for both exposure groups, however, both were higher than the designated significant risk level (= 10(-3)) which was defined by the US Supreme Court in 1980. Considering the bioavailability of particle-bound PAHs still remains unknown, the health risks obtained from this study could be overestimated and thus require further investigation.     

Detoxification and oxidative stress responses along with microcystins accumulation in Japanese quail exposed to cyanobacterial biomass

The cyanobacterial exposure has been implicated in mass mortalities of wild birds, but information on the actual effects of cyanobacteria on birds in controlled studies is missing. Effects on detoxification and antioxidant parameters as well as bioaccumulation of microcystins (MCs) were studied in birds after sub-lethal exposure to natural cyanobacterial biomass. Four treatment groups of model species Japanese quail (Coturnix coturnix japonica) were exposed to controlled doses of cyanobacterial bloom during acute (10 days) and sub-chronic (30 days) experiment. The daily doses of cyanobacterial biomass corresponded to 0.2-224.6 ng MCs/g body weight. Significant accumulation of MCs was observed in the liver for both test durations and slight accumulation also in the muscles of the highest treatment group from acute test. The greatest accumulation was observed in the liver of the highest treatment group in the acute test reaching average concentration of 43.7 ng MCs/g fresh weight. The parameters of detoxification metabolism and oxidative stress were studied in the liver, heart and brain. The cyanobacterial exposure caused an increase of activity of cytochrome P-450-dependent 7-ethoxyresorufin O-deethylase representing the activation phase of detoxification metabolism. Also the conjugation phase of detoxification, namely the activity of glutathione-S-transferase, was altered. Cyanobacterial exposure also modulated oxidative stress responses including the level of glutathione and activities of glutathione-related enzymes and caused increase in lipid peroxidation. The overall pattern of detoxification parameters and oxidative stress responses clearly separated the control and the lowest exposure group from all the higher exposed groups. This is the first controlled study documenting the induction of oxidative stress along with MCs accumulation in birds exposed to natural cyanobacterial biomass. The data also suggest that increased activities of detoxification enzymes could lead to greater biotransformation and elimination of the MCs at the longer exposure time.     

Enhanced immunological and detoxification responses in Pacific oysters, Crassostrea gigas, exposed to chemically dispersed oil

The aim of this study was to evaluate the effects of chemically dispersed oil on an economically and ecologically important species inhabiting coasts and estuaries, the Pacific oyster Crassostrea gigas. Studies were carried out with juveniles, known to generally be more sensitive to environmental stress than adults. A set of enzyme activities involved in immune defence mechanisms and detoxification processes, i.e. superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), catecholase-type phenoloxidase (PO), laccase-type PO and lysozyme were analysed in different oyster tissues, i.e. the gills, digestive gland and mantle, and in the plasma and the haemoycte lysate supernatant (HLS) of the haemolymph. Results indicated that total PAH body burdens were 2.7 times higher in the presence than in the absence of the chemical dispersant. After 2 days of exposure to chemically dispersed oil, alkylated naphthalenes accounted for 55% of the total PAH body burden, whereas alkylated fluorenes and alkylated dibenzothiophenes accounted for 80% when the chemical dispersant was absent. Importantly, a higher number of enzyme activities were modified when oil was chemically dispersed, especially in the plasma and gills. Moreover, independently of the presence or absence of chemical dispersant, oil exposure generally inhibited enzyme activities in the gills and plasma, while they were generally activated in the mantle and haemocytes. These results suggest that the gills and plasma constitute sensitive compartments in C. gigas, and that the mantle and haemocytes may play an important role in protection against xenobiotics. Among the six enzyme activities that were analysed in these body compartments, five were modulated in the chemical dispersion (CD) treatment while only half of the enzyme activities were modulated in the mechanical dispersion treatment. Furthermore, CD treatment effects were often observed following exposure, but also during depuration periods. These results suggest that immune and/or detoxification responses are likely to be affected when dispersants are used to treat oil spills in shallow waters.     

Salinity influences glutathione S-transferase activity and lipid peroxidation responses in the Crassostrea gigas oyster exposed to diesel oil

Biochemical responses in bivalve mollusks are commonly employed in environmental studies as biomarkers of aquatic contamination. The present study evaluated the possible influence of salinity (35, 25, 15 and 9 ppt) in the biomarker responses of Crassostrea gigas oysters exposed to diesel at different nominal concentrations (0.01, 0.1 and 1 mL.L^− 1) using a semi-static exposure system. Salinity alone did not resulted in major changes in the gill's catalase activity (CAT), glutathione S-transferase activity (GST) and lipid peroxidation levels (measured as malondialdehyde, MDA), but influenced diesel related responses. At 25 ppt salinity, but not at the other salinity levels, oysters exposed to diesel showed a strikingly positive concentration-dependent GST response. At 25 ppt and 1 mL.L^− 1 diesel, the GST activity in the gills remained elevated, even after one week of depuration in clean water. The increased MDA levels in the oysters exposed to diesel comparing to control groups at 9, 15 and 35 ppt salinities suggest the occurrence of lipid peroxidation in those salinities, but not at 25 ppt salinity. The MDA quickly returned to basal levels after 24 h of depuration. CAT activity was unaltered by the treatments employed. High toxicity for 1 mL.L^− 1 diesel was observed only at 35 ppt salinity, but not in the other salinities. Results from this study strongly suggest that salinity influences the diesel related biomarker responses and toxicity in C. gigas, and that some of those responses remain altered even after depuration.     

上海船厂2E7-1地块项目施工中的BIM应用

BIM的核心理念和价值是实现建设项目的全寿命周期管理。以上海船厂2E7-1地块工程项目为例,对BIM应用的组织模式以及项目设计、施工及竣工阶段的具体内容进行探索和实践,为建设项目全过程应用BIM技术提供一个较好的范本。     

Shifts of soil enzyme activities in wetlands exposed to elevated CO(2)

Wetlands play a key role in global biogeochemical cycles, and as such, the effects of global climatic changes on these systems are of great importance. In this study, we assessed impacts of elevated CO(2) on soil enzyme activities in different types of wetlands. We hypothesised that elevated CO(2), by increasing DOC supply into the soil, would modify enzyme activities. Intact soil cores collected from four wetlands (a bog, a fen, a gully mire, and a marsh) in north Wales and Korea were incubated either under ambient conditions (370 ppm) or elevated CO(2) conditions (double ambient) for 4-2 months. Elevated CO(2) increased DOC concentrations in the pore-water, by which soil microbes appeared to be affected. Enzyme activities exhibited various responses. For example, elevated CO(2) had no effect on beta-glucosidase activity in any soil, suggesting little direct impact on carbon mineralisation. However, N-acetylglucosaminidase activity increased significantly (P<0.05, n=5) in the cores from the bog, whilst a similar response was found in the gully mire for phosphatase activity. Such changes were absent from the fen and marsh where inorganic nutrients were abundant, suggesting that enzyme activities involved in N or P mineralisation only increase under elevated CO(2) when nutrient limitation is strongly exerted.     

Accumulation of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) among workers occupationally exposed to carbon disulfide for 1 week

OBJECTIVES: To investigate if carbon disulfide (CS(2)) accumulates after a 1-week exposure period, and how the work-shift duration and exposure magnitude affects this accumulation for the workers in viscose rayon industry. METHODS: Six 8-h and seven 12-h workers in the spinning department historically known to be exposed to high air CS(2) were recruited as the exposed groups. Seven workers from other non-CS(2)-exposed departments were recruited as non-exposure controls. Exposure monitoring covered a full work shift with personal breathing zone monitoring. Urine was collected pre- and post-shift every day throughout the 5 consecutive days. 2-Thiothiazolidine-4-carboxylic acid levels in the urine (U-TTCA) were determined. RESULTS: No detectable values were found for airborne (<0.6 ppm) and urinary (<35 ng/ml) monitoring for the control groups. The exposure levels for a 12-h shift (11.3+/-1.47) (AM+/-S.D.) were significantly greater than for an 8-h shift (6.3+/-0.64). The linear accumulation trend for daily U-TTCA across the workdays was only significant for the 12-h shift at pre-shift. Statistical significance was found in the regression of the ratios for pre-shift U-TTCA to airborne CS(2) levels on the preceding day to the day of the exposure at pre-shift for a 12-h shift (r=0.98, P=0.02). CONCLUSIONS: The U-TTCA accumulation for occupational exposure to CS(2) was exposure-magnitude-dependent. The linear equations derived in this study indicated that the U-TTCA increment at pre-shift for each additional daily 12-h exposure, after an adjustment for the CS(2) exposure level, was 0.02 mg/g creatinine/ppm of CS(2). The long-term exposure response under such repeated and intermittent conditions should be noteworthy.     

Cytochrome P450 1B1 mRNA levels in peripheral blood cells and exposure to polycyclic aromatic hydrocarbons in Chinese coke oven workers

Cytochrome P450 1B1 (CYP1B1) is induced through the Ah receptor and is involved in the activation of polycyclic aromatic hydrocarbons (PAHs). To determine the validity of a quantitative analysis of CYP1B1 mRNA in peripheral human blood cells for the estimation of PAH exposure, a real-time quantitative polymerase chain reaction method was used to measure the relative levels of CYP1B1 mRNA in 37 Chinese coke oven workers and 13 control workers. A large inter-individual difference in the levels was observed. The average level of the CYP1B1 mRNA in workers at the top work site, where the PAH exposure level from the coke ovens was highest, was significantly higher than in workers at the middle site (P<0.01) or the controls (P=0.02). A non-significant positive correlation was found between the CYP1B1 mRNA levels and urinary 1-hydroxypyrene (R=0.22, P=0.13), and a significant correlation between these mRNA levels and urinary cotinine (R=0.33, P=0.02). It was interesting that a significant positive correlation between CYP1B1 mRNA and 1-hydroxypyrene was observed in subjects with the Leu/Leu type of CYP1B1 Leu432Val polymorphism (R=0.33, P=0.02, n=38) and a non-significant correlation in subjects with the Leu/Val and Val/Val types (R=-0.36, P=0.25, n=12), although the number of subjects in this strata analysis was small. Our preliminary study suggests that PAH exposure in coke ovens and smoking maybe associated with CYP1B1 mRNA levels in peripheral blood cells although mRNA is generally unstable and could be expressed following exposure to other agents.     

Trans-generational and neonatal humoral immune responses in West Greenland sledge dogs (Canis familiaris) exposed to organohalogenated environmental contaminants

Previous investigations in the Arctic have suggested OHC (organohalogen contaminant) induced immune toxic effects on e.g. polar bears (Ursus maritimus). We therefore studied the dietary impact from minke whale blubber (Balaenoptera acutorostrata), rich in polyunsaturated fatty acids and OHCs, on the humoral immunity of 7 captive West Greenland sledge dog (Canis familiaris) bitches and their 4 pups constituting a sentinel model species for polar bears. A control group was composed of 8 bitches and their 5 pups all fed pork (Suis scrofa) fat. The study included serum IgG measurements (bitches and pups) and specific immune responses towards tetanus toxoid (bitches) and diphtheria toxoid (pups) as well as influenza virus (pups). The analyses showed that IgG concentrations were non-significantly lowest in exposed bitches and pups (t-test: all p > 0.05). In addition, significant lower antibody response was detected in exposed pups immunized with influenza virus at age 3 months (t-test: both p < 0.05). No clear group differences were found for tetanus toxoid in bitches and diphtheria toxoid in pups. The results suggest that the humoral immune system of sledge dogs may be suppressed by the dietary blubber composition of OHCs and polyunsaturated fatty acids while a larger follow-up study is recommended in order to investigate this relationship further.     

Variations in the hepatopancreatic α-amylase activity in fishes exposed to some industrial pollutants

The liver in some fishes is associated with intrahepatic pancreas (hepatopancreas). The present investigation deals with the effect of some industrial pollutants on the hepatopancreatic α-amylase activity in two air-breathing freshwater teleosts: Ophicephalus punctatus (Bloch) and Clarias batrachus (Linn.). High degrees of inhibition are noted in isolated treatments with the toxicants and the composite factory effluent. Although the concentrations of the pollutants used show similar survival rates, they differ significantly in their extent of action. The low dose of the pollutants producing only 10% death are no less physiologically effective than the TL_m doses. 90 days' chronic exposure to the undiluted factory effluent caused no mortality, but produced inhibitions of a very high degree.     

A common matrix metalloproteinase (MMP)-2 polymorphism affects plasma MMP-2 levels in subjects environmentally exposed to mercury

Mercury (Hg) exposure is associated with disease conditions, including cardiovascular problems. Although the mechanisms implicated in these complications have not been precisely defined yet, matrix metalloproteinases (MMPs) may be involved. The gene encoding MMP-2 presents genetic polymorphisms which affect the expression and activity level of this enzyme. A common polymorphism of MMP-2 gene is the C⁻¹³⁰⁶T (rs 243865), which is known to disrupt a Sp1-type promoter site (CCACC box), thus leading to lower promoter activity associated with the T allele. This study aimed at examining how this polymorphism affects the circulating MMP-2 levels and its endogenous inhibitor, the tissue inhibitor of metalloproteinase-2 (TIMP-2) in 210 subjects environmentally exposed to Hg. Total blood and plasma Hg concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). MMP-2 and TIMP-2 concentrations were measured in plasma samples by gelatin zymography and ELISA, respectively. Genotypes for the C⁻¹³⁰⁶T polymorphism were determined by Taqman® Allele Discrimination assay. We found a positive association (p = 0.0057) between plasma Hg concentrations and MMP-2/TIMP-2 (an index of net MMP-2 activity). The C⁻¹³⁰⁶T polymorphism modified MMP-2 concentrations (p = 0.0465) and MMP-2/TIMP-2 ratio (p = 0.0060) in subjects exposed to Hg, with higher MMP-2 levels been found in subjects carrying the C allele. These findings suggest a significant interaction between the C⁻¹³⁰⁶T polymorphism and Hg exposure, possibly increasing the risk of developing diseases in subjects with the C allele.     

出口蒙古60E1钢轨系列单开道岔的研制

根据蒙古扎门乌德物流园专用线建设需要,结合铺设实际线路情况,设计用于1 435 mm,1 520 mm两种轨距的单开道岔,介绍了道岔的结构设计,并对舒适度参数、外轨欠超高、轨距加宽等进行了检算评估。     

Induction of CYP1A and DNA damage in the fathead minnow (Pimephales promelas) following exposure to biosolids

Biosolids (treated sewage sludge) are increasingly disposed of on land. Thus particle-sorbed and dissolved constituents have the potential to enter nearby watersheds. Although organic contaminants are known to be present in biosolids these are not currently regulated and little data exist on their potential toxicity to aquatic organisms. We exposed Pimephales promelas to two concentrations of biosolids (0.5 and 2.5 g l(-1)) for 28-days (static-renewal) and characterized contaminants present and the extent of CYP1A and DNA damage induction at various time points. Many organic contaminants were detected in the biosolids, with polycyclic aromatic hydrocarbons (PAHs) being the dominant class. Substantial levels of polybrominated diphenyl ethers (PBDEs) and nonylphenols (NPs) were also present. Significant induction of hepatic CYP1A protein compared with controls (P<0.05) was observed in both low (0.5 g l(-1)) and high (2.5 g l(-1)) exposed fish from Day 7. CYP1A levels peaked at Day 21 with 21-fold and 8-fold inductions over controls in high and low dose fish respectively. Induction of DNA damage in hepatocytes (single strand breaks as measured using the COMET assay) was observed in both exposures compared with controls on Days 14 and 28 (P<0.05). A significant correlation was found between CYP1A induction and DNA damage (Pearson correlation index, P<0.05). It is plausible that activation of PAHs may be responsible for the induction of CYP1A and resulting increase in DNA damage. Our data show the potential for detrimental effects in the event of exposure of aquatic organisms to biosolids and the need for further investigations of possible impacts due to constituents not covered by current guidelines.     

建筑施工中如何对4M1E进行质量控制

结合工作经验,介绍了施工方在建筑施工中如何对影响工程惯量的五个因素——人、材料、机械、方法和环境进行质量控制的思路和方法,通过工程实例证明了这些控制方法的可行性。     

Comparative study of the estrogenic responses of mirror carp (Cyprinus carpio) exposed to treated municipal sewage effluent (Lisbon) during two periods in different seasons

To assess the estrogenic potency of the treated domestic sewage effluent from a sewage treatment plant (STP) located in Lisbon (Chelas), 60 mirror carp (Cyprinus carpio) were exposed to different concentrations of the sewage effluent (0%, 25%, 50% and 100%) for two periods of 28 days in two different seasons (winter/spring). Vitellogenin induction in males was used as a biomarker of exposure to xenoestrogens. At the end of the experiment, blood samples were taken for vitellogenin analysis and the fish were sacrificed and dissected. Gonad samples were taken for histological evaluation of the sewage effects. The results showed an increase in vitellogenin induction in exposed fish, both males and females, depending on the different dilutions of the sewage effluent. In comparison with controls, the gonadosomatic index decreased significantly (P < 0.05) in fish exposed to 100% treated effluent. Although statistically not significant, the hepatosomatic index (HSI) was high in all exposed fish. Histological abnormalities in fish gonads were evaluated and related to the different percentages of sewage effluent. Seasonal variations found in estrogenic responses were attributed to weather influences on sewage dilution.     

Gill and head kidney antioxidant processes and innate immune system responses of yellow perch (Perca flavescens) exposed to different contaminants in the St. Lawrence River, Canada

Biomarkers of oxidative stress metabolism and the innate immune response were examined in gill and head kidney tissue of wild-caught yellow perch (Perca flavescens) collected from four sites ranging in type and degree of metal pollution in the St. Lawrence River, Quebec, Canada. Sites were ranked as follows: Île Dorval < Îles aux Sables < Îlet Vert < Beauharnois. Biomarker measurements did not correspond completely to the perceived pollution gradient. Total protein content was highest at a site 4 km downstream of municipal effluents (Îlet Vert) exposed to moderate and high levels of heavy metals and faecal coliforms, respectively. Thiol content was highest at the reference site (Île Dorval) with the lowest contaminant levels. Glutathione-S-transferase (GST) activity was highest in fish from the site furthest downstream that was exposed to moderate metal contamination (Îles aux Sables). Glutathione reductase (GRd) activity was high in both gill and head kidney tissue of fish from the reference site (Île Dorval) and highest in the kidney of fish from the most contaminated site (Beauharnois). Catalase activity was highest in head kidney tissue in fish from this latter site. Ceruloplasmin activity was lowest in head kidney from fish collected at the reference site and highest at Beauharnois. Lysozyme activity was lowest in head kidney tissue from fish at the reference site and highest in tissue from fish at Îlet Vert, downstream of municipal effluents. These results suggest that the direction and magnitude of oxidative stress biomarker response and innate immune function biomarker response vary between tissues and among complex mixtures of contaminants, complicating interpretation of results. Results further suggest that bacterial loading, as measured by faecal coliforms, affects the oxidative stress metabolism and the innate immune response.